Persons who own or use power woodworking tools often use table saws and other power woodworking tools in close succession, while shaping and assembling wooden boards and other workpieces into finished products including furniture. Typically, wooden boards and other workpieces are sawed into components by use of a table saw, which may then be joined together by use of dados (rectangular grooves) formed in one or more components, into which other components may be fitted and fastened. The separate operations of sawing and of dado formation may be performed by separate tools or by changing components of a single tool.
Performance of successive woodworking operations, including sawing wooden boards and forming dados in such boards, can be greatly enhanced by the use of separate tools in convenient proximity. Additionally, production of larger finished products including furniture can be greatly enhanced by enlargement of the work surface of a conventional table saw, and table saws are commonly provided with connecting means, to which extension surfaces (wings), available as accessories, can be connected. (U.S. Pat No. 3,695,189).
Conventional dado blades are readily available, which are designed to replace the circular saw blades of a conventional table saw, and can be used to form the dado or dados of the desired width and depth in wooden boards or other workpieces.
The need for the combination of a conventional table saw and a dado-forming tool, in convenient proximity in an enlarged work surface, is demonstrated by the joining of two table saws, one of which is permanently fitted with dado blades (Appendix 1, Popular Woodworking, Issue #135; August 2003, Pages 64–65). However, this equipment combination is very expensive, and requires more space than is available to many users.
The use of a single table saw, by replacement of the existing table saw blade with such dado blades whenever a dado is required, has important disadvantages. Such replacement requires that use of the table saw must be interrupted; removal of the circular table saw blade and its replacement by the dado blades requires significant time, the use of tools and manual dexterity; the vertical position of the dado blades must be adjusted and verified and the dado blades must be removed and replaced by the saw blade for the next work phase and the vertical position of the saw blade must be adjusted. Users often drop parts, such as the nut or washer used to retain the table saw and dado blades, while replacing the blades. Multiple repetitions of these steps are required in the fabrication of furniture and other products.
Combining several power tools in a single machine has been disclosed in various complicated devices (U.S. Pat. No. 1,030,598; U.S. Pat. No. 3,734,151; U.S. Pat. No. 4,265,283; U.S. Pat. No. 5,865,228; U.S. Pat. No. 5,890,521) and combining a table saw with another power tool mounted on an extension wing has been disclosed (U.S. Pat. No. 4,887,653).
However, a power tool attachment for a table saw has not been disclosed that is adjustable, lightweight and relatively simple, that can be mounted under an extension wing of a conventional table saw and that has a cutting element that can be vertically adjusted to a desired position, and lowered below the extension wing surface when not in use.
Specifically, such a power tool attachment has not been described in which the cutting element is a dado blade, a set of dado blades, or another circular cutting element such as a circular saw.